Removal of heavy metals from petroleum stocks



United States Patent 2,854,399: REMOVAL OF HEAVY'METALS FROM PETROLEUM srocrrs 801 W. Weller, Drexel Hill, Pa.,. assig'nor to. Houdry Process'Corporafion wilmington, Del., a corporation of Delaware No Drawing. Continuation'of application Serial No.

267,307, January 19, 1952. This application September 21, 1954,:Serial. No. 457,569:

3 Claims; (Gl. 208-88) The present invention relates .-to a process for the removal of'heavy' metals or compounds thereof, such as heavy metaloxides, from hydrocarbon stocks and more particularly. to a process for the removal of relatively smallamounts of heavy'nie'tals or. their compounds from petroleum and other" hydrocarbon-feed stocks which aretorbe subjected to catalytic conversion operations, such as cracking, reforming, dehydrogenation, and the like.

It is wellkn'own'th'at'many hydrocarbon feed stocks contain appreciable amounts of'he'a-vy'metalslor compounds thereof, such'as lead; iron, nickel and copper or their compounds. It is also known that such heavy metals or metal compounds are liable to deteriorate the activity of and even to poison certain types of catalysts, when such metal-containing feed stocks are subjected to a treatment in the presence of such types of catalysts. Thus, cracking catalysts, such as silica-alumina catalysts alone or in admixture with other metal'oxides suitable for this purpose, are deteriorated or poisoned by heavy metals, such as vanadium, iron, nickel and copper, and dehydrogenation catalysts of the group of platinum and palladium metals are poisoned by lead, tin, arsenic, mercury and the like.

It is an object of the present invention to prevent the deterioration and poisoning of hydrocarbon conversion catalysts by removal of heavy metals and their compounds from hydrocarbon feed stocks containing them.

It is another object of the present invention to remove heavy metals and their compounds from hydrocarbon stocks containing the same, in a simple and economical manner.

It is a further object of the present invention to remove from hydrocarbon conversion stocks such heavy metals as lead, iron, nickel and copper and compounds thereof which are capable of deteriorating and poisoning hydrocarbon conversion catalysts.

Other objects and advantages of the present invention will be apparent from the subsequent description and the claims.

It has been found that heavy metals, such as, for instance, lead, iron, nickel, and copper and certain compounds thereof, may easily and substantially completely be removed from hydrocarbons and hydrocarbon mixtures, particularly from hydrocarbon feed stocks to be subjected to catalytic treatment, by subjecting these hydrocarbons or hydrocarbon mixtures containing such heavy metals to a treatment with elementary sulfur, thereby forming sulfides of the heavy metals, which sulfides are insoluble in the hydrocarbons under treatment.

Various methods may be used for this treatment of hydrocarbon feed stocks containing heavy metals with elementary sulfur.

One of these methods consists in passing the heavy metal-containing feed stocks in the liquid or gaseous state through a bed of solid, powdered or granular elemental sulfur, preferably at a temperature between room temperature and about 30 F. In order to minimize the 5:. solubility 'of th'e sulfur in'heavy'feed stocks, we prefer to use solid'sulfur offespec'ially low solubility, thatis, sulfur m convenien'tly designated as S obtained by rapid cooling .eithero'fsulfur vapor orof liquid sulfur iA'notlier-method 'of 'the treatment of the hydrocarbon feed's'tocks containingheavy metals, or the like, with elementary. sulfur consists in scrubbing these feed stocks with liquidsulfur, preferably in the temperature range of about 250-320 FL As liquid sulfur has a low, almost constant viscosity (of about 10 centipoises). in this temperature range, while its vapor pressure is very low (about 0.37'mm. Hg-at 320 K), the treatment-in this temperature range is particularly=-simple= and convenient.

Other methods for. the treatment of hydrocarbons and hydrocarbon mixtures with=elementary sulfur in order to remove heavy metals and rnetal compounds from such hydrocarbons and hydrocarbon mixtures can also be employedwithin the scope of the present invention.

Any. relatively small amount of sulfur which'might be introduced 'by the "treatment according ,to the present 'inventioninto the hydrocarbon. feed stock, or the like, will not injure 'cracking cat alystsfree of iron, nickel, copper,,or the-like, ordehydrogenation metal catalysts,

such as platinum or. palladium.-

One and .-the same batch. of: elemental sulfur may be iised'in any of "these methods for the treatment of a very large amount of hydrocarbons, particularly since the percentage of heavy metals contained therein generally will be small. If and when desired, however, the sulfur employed may be freed from the metal sulfides formed and accumulated therein by any suitable method, such as by a filtration of the liquefied sulfur, or by an extraction of the sulfur by a volatile organic solvent such as carbon disulfide.

Example I A hydrocarbon feed stock to be used in catalytic conversion processes and containing relatively small, but appreciable amounts of such heavy metals as lead, iron, nickel and/or copper is continuously passed in the liquid state at a temperature of about F. through a bed of solid powdered sulfur (SW). The heavy metals are retained in the sulfur bed and thus removed by this treatment from the hydrocarbon. stock. Treatment at temperatures up to about 210 F. is likewise eifective.

Example 11 A naphtha stock, having an initial boiling point of 163 F. and an end point of 214 F., containing heavy metals including 2 parts per million (p. p. m.) of lead was treated with 0.1% flowers of sulfur at room temperature. This stock was filtered after the treatment and was found to contain less than 0.5 p. p. m. of lead.

Example III Another sample of the same naptha used in Example II was treated with 0.01% solid sulfur and then distilled. The distillate tested free of lead.

Example IV carbons and it is desired to remove suchsulfur from these hydrocarbons beforefurther treating them, this may be done by any of the usual andknown methods for the removal of relatively small amounts of sulfur from hydrocarbons. Generally, however, the small amounts of sulfur which might be incorporated into the hydrocarbons by the treatment described will not be disadvantageous in further-treatment of the hydrocarbons, particularly in catalytic conversion. operations, and will not injure cracking catalysts free of iron, nickel or the like, or platinum metal dehydrogenation catalysts.

.Obviously many modifications and variations of the invention as hereinbefore set forth may be made without departing from the. spirit and scope thereof and therefore only such limitations should be imposed as are indicated in the appended claims.

This application is a continuation of application Serial No. 267,307, filed January 19, 1952, now abandoned.

What is claimed is:

1. The process of converting liquid hydrocarbon feed stock containing relatively small amounts of heavy. metals which includes the steps of subjecting said hydrocarbon feed stock to'the ,action of elementary sulfur to bring about the formation of heavy metal sulfides, separating a fraction having a reduced content of heavy metals and heavy metal sulfides, said fraction containing substana,ss4,sao

,tially all of said hydrocarbon feed stock, and thereafter subjecting the thus metal-freed hydrocarbon to a conversion treatment in the presence of a catalyst readily poisoned by heavy metals, said catalytic conversion treatment being at an elevated temperature.

2. The method of claim 1 in which the elementary sulfur is in the Sp. form.

3. In the process of catalytically cracking petroleum fractions derived from crude oils containing heavy metal components deleterious in the catalytic cracking of such oils, the improvement which comprises subjecting an oil containing such heavy metal components to contact with elementary sulfur, reacting said sulfur with said components and forming insoluble heavy metal sulfides, and removing said heavy metal sulfides and excess sulfiding agent from the oil prior to contact of the oil with the cracking catalyst.

References Cited in the file of this patent UNITED STATES PATENTS 1,221,698 Day Apr. 3, 1917 2,163,245 Laughlin June 20, 1939 2,187,741 Houdry Ian. 23, 1940 2,232,909 Gohr Feb. 25, 1941 2,466,050 Shabaker et al. Apr. 5, 1949 2,466,051 Shabaker et al. Apr. 5, 1949 2,515,141 Stripling July 11, 1950 2,683,683 Mills July 13, 1954 UNITED STATES PATENT OFFICE Certificate of Correction Patent No. 2,854,399 September 30, 1958 Sol W. Weller It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1, line 72, for 30 F. read 230 F.; column 2, line 3, for sulfuT m read sulfur mu.

Signed and sealed this 24th day of February 1959.

[SEAL] Attesb KARL H. AXLINE, ROBERT C. WATSON, Attesting OfliGe r. ommz'ssz'oner of Patents. 

1. THE PROCESS OF CONVERTING LIQUID HYDROCARBON FEED STOCK CONTAINING RELATIVELY SMALL AMOUNTS OF HEAVY METALS WHICH INCLUDES THE STEPS OF SUBJECTING SAID HYDROCARBONS FEED STOCK TO THE ACTION OF ELEMENTARY SULFUR TO BRING ABOUT THE FORMATION OF HEAVY METAL SULFIDES, SEPARATING A FRACTION HAVING A REDUCED CONTENT OF HEAVY METALS AND HEAVY METAL SULFIDES, SAID FRACTION CONTAINING SUBSTANTIALLY ALL OF SAID HYDROCARBON FEED STOCK, AND THEREAFTER SUBJECTING THE THUS METAL-FREED HYDROCARBON TO A CONVERSION TREATMENT IN THE PRESENCE OF A CATALYST READILY POISONED BY HEAVY METALS, SAID CATALYTIC CONVERSION TREATMENT BEING AT AN ELEVATED TEMPERATURE. 